[Gradle] Legacy metadata compilation should contain all source sets from

depends on closure of its default source set.

With HMPP it is no longer needed, since each source compiles
independently and sees its parent declarations via klib dependencies

cherry-picked from 3c34354

^KT-55730 Verification Pending

Author: antohaby

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/metadata/KotlinMetadataTargetConfigurator.kt

@@ -74,6 +74,12 @@ class KotlinMetadataTargetConfigurator :
                 if (isCompatibilityMetadataVariantEnabled) {
                     // Force the default 'main' compilation to produce *.kotlin_metadata regardless of the klib feature flag.
                     forceCompilationToKotlinMetadata = true
+                    // Add directly dependsOn sources for Legacy Compatibility Metadata variant
+                    // it isn't necessary for KLib compilations
+                    // see [KotlinCompilationSourceSetInclusion.AddSourcesWithoutDependsOnClosure]
+                    defaultSourceSet.internal.dependsOnClosure.forAll {
+                        source(it)
+                    }
                 } else {
                     // Clear the dependencies of the compilation so that they don't take time resolving during task graph construction:
                     compileDependencyFiles = target.project.files()

libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/KT55730CommonMainDependsOnAnotherSourceSet.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+@file:Suppress("FunctionName")
+
+package org.jetbrains.kotlin.gradle
+
+import org.jetbrains.kotlin.gradle.dsl.multiplatformExtension
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class KT55730CommonMainDependsOnAnotherSourceSet {
+    @Test
+    fun `legacy metadata compilation should have commonMain with its depends on closure`() {
+        val project = buildProject {
+            enableCompatibilityMetadataVariant()
+            applyMultiplatformPlugin()
+            kotlin {
+                val grandCommonMain = sourceSets.create("grandCommonMain")
+                val commonMain = sourceSets.getByName("commonMain")
+                commonMain.dependsOn(grandCommonMain)
+            }
+        }
+
+        project.evaluate()
+
+        val actualSourceSets = project
+            .multiplatformExtension
+            .metadata()
+            .compilations
+            .getByName("main")
+            .kotlinSourceSets
+            .map { it.name }
+            .toSet()
+
+        assertEquals(setOf("grandCommonMain", "commonMain"), actualSourceSets)
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/buildProject.kt

@@ -63,4 +63,8 @@ fun Project.androidLibrary(code: LibraryExtension.() -> Unit) {
 fun Project.projectModel(code: KotlinPm20ProjectExtension.() -> Unit) {
     val extension = project.extensions.getByType(KotlinPm20ProjectExtension::class.java)
     extension.code()
-}
+}
+
+fun Project.enableCompatibilityMetadataVariant(enabled: Boolean = true) {
+    propertiesExtension.set("kotlin.mpp.enableCompatibilityMetadataVariant", enabled.toString())
+}